package com.hnjme.cnec.gateway.config;

import lombok.extern.slf4j.Slf4j;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpMethod;
import org.springframework.http.HttpStatus;
import org.springframework.http.server.reactive.ServerHttpRequest;
import org.springframework.http.server.reactive.ServerHttpResponse;
import org.springframework.web.cors.reactive.CorsUtils;
import org.springframework.web.server.ServerWebExchange;
import org.springframework.web.server.WebFilter;
import org.springframework.web.server.WebFilterChain;

/**
 * 配置网关的web跨域访问
 *
 * @author Luo Liang
 */
@Slf4j
@Configuration
public class GatewayConfig {

    private static final String ALLOWED_HEADERS = "*";
    private static final String ALLOWED_METHODS = "GET, PUT, POST, DELETE, OPTIONS";
    private static final String ALLOWED_ORIGIN = "*";
    private static final String MAX_AGE = "3600";

    @Bean
    public WebFilter corsFilter() {
        log.debug("网关跨域处理");
        return (ServerWebExchange ctx, WebFilterChain chain) -> {
            ServerHttpRequest request = ctx.getRequest();
            log.debug("网关跨域处理:{}", request.getPath());
            if (CorsUtils.isCorsRequest(request)) {
                ServerHttpResponse response = ctx.getResponse();
                HttpHeaders headers = response.getHeaders();
                headers.add("Access-Control-Allow-Origin", ALLOWED_ORIGIN);
                headers.add("Access-Control-Allow-Methods", ALLOWED_METHODS);
                headers.add("Access-Control-Max-Age", MAX_AGE);
                headers.add("Access-Control-Allow-Headers", ALLOWED_HEADERS);
                if (request.getMethod() == HttpMethod.OPTIONS) {
                    response.setStatusCode(HttpStatus.OK);
                    return response.setComplete();
                }
            }
            return chain.filter(ctx.mutate().request(request).build());
        };
    }
}
